t_dd_dmatmp: Disallow flat shading when rendering quad strips via tri strips
t_dd_dmatmp: Disallow flat shading when rendering quad strips via tri strips

When rendering quad strips via tri strips we can't get the provoking
vertex right, so disallow flat shading.

v2: Major rebase on top of Ian's other t_dd_dmatmp.h work.

Signed-off-by: Ville Syrjälä <cd6e8d405ca90be3a03d5427c5b24fbd2d68dcc4@linux.intel.com>
Signed-off-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler